1. Field of the Invention
The present disclosure relates to columns used to support structures and in particular to lally columns that can be adjusted in height.
2. Description of the Related Art
Permanent structural columns, such as lally columns, are often pre-fabricated and cut to size at the construction site to fit the actual height needed for a particular application. The cutting, assembling and installing of the column is a time consuming process that can undesirably require specialized tools and skilled labor.
Adjustable columns that have been developed to address this problem are typically telescopic in nature with a first tubular post sliding within a second tubular post. A crossbar is inserted through holes aligned in the first and second posts to fix the height of the column. A cap plate is connected to a threaded bar and the bar is then rotated to elevate the cap plate for the final height adjustment. These adjustable columns, however, can be load limited compared to traditional lally type columns and are vulnerable to tampering. Alternative adjustable columns insert one or more shim plates at the base to increase the height of the column while the column is manually held upright for connection with preexisting apertures in a beam. Both of these configurations require multiple personnel to retain the column in position while the height of the column is adjusted and the alignment secured.
Columns have traditionally been assumed to support a load that also provides an adequate counterforce against uplifting forces. This tradition is incorporated into many residential and commercial building codes by the omission of a requirement that columns connect to the floor and supported beam. As a result, in many installations columns are simply placed in a load bearing position without being positively secured to the floor and beam. A secure connection between the column, floor and beam that can provide the uplift protection is being increasing recognized as an important structural element under severe weather or environmental conditions.
An adjustable column is needed that can be readily installed by a single worker with the use of readily available tools that can also advantageously provide uplift protection.